The Shepper app allows you to actively look for tasks in your defined areas or nearby, based on your current location.
Tap into the Market and you can choose to see tasks that are Nearby. You can tap the icon in the top-right corner of the screen to alternate between a list and a map view, which will allow you to view the locations of available tasks.
If there is nothing available, you can always try looking around the map to see if there are any available jobs a little further afield!
The Shepper app will send a 'Morning Minute' notification at during the week, summarising available tasks. You may also receive notifications for any tasks that are available to be completed that day.